Joshua Colwell, Adrienne Dove, and James Cooney

Walkabout the Galaxy

Science EN ↓ 369 episodes

An irreverent and informative tour of the latest, greatest, and most interesting discoveries in astronomy.

Author

Joshua Colwell, Adrienne Dove, and James Cooney

Category

Science

Latest episode

Jul 9, 2026

Where to listen?

Podcasts in the app Replaio Radio Coming soon

Podcasts are coming to the app soon. Install now and be the first to see a whole new take on podcasts

Get it on Google Play Install for free Android 5M+ downloads · 4.8 rating iOS soon

Episodes

Not All Supernovae Are Created Equal 20.11.2024

If you're speaking English, not Latin, do you really have to say "supernovae" instead of "supernovas"? Also, they are, in some sense, created equally: explosion of a white dwarf, but the outcomes are not all equal . You are welcome for this grammatical tangent, and please enjoy our fun discussion about weird tesserae (more Latin!) on Venus and the whole standard candle story of type 1a supernovae...

Is There Another Belt of Comets? 06.11.2024

New observations contradict earlier studies about the possibility of another belt of comets orbiting the Sun twice as far away as Pluto. We'll take a look at what's what in the outer solar system and also explore whether black holes may help explain the Hubble tension. We also play FLOD (Flyby, Land, Orbit, Destroy) and have some "how many planets" trivia.

Trojan Asteroids Everywhere 30.10.2024

Join Strange and Down quarks for a close look at Trojan asteroids, the forgotten asteroids of the solar system. NASA's Lucy mission is en route to take our first close look at these denizens of the outer solar system and has an Earth gravity assist in December 2024. As you'll see in our trivia, the numbers of Trojans may surprise you. Jupiter is the king of the Trojans, but we'll take a closer loo...

Basin Instinct - Cosmological Structure and Edible Asteroids 23.10.2024

We get a tour of our place in the grand cosmological scheme of things with new mapping of the local Basin of Attraction. Spoiler: also Jim's new stage name. And we explore the final frontier of In Situ Resource Utilization with studies of how to get edible nutrients from the raw materials in asteroids. It's a little bit gross. Plus space news, trivia, and more. Join us to learn about all this (and...

OG Top Goes to Europa 09.10.2024

Original Top Quark Dr. Tracy Becker returns to her old stomping grounds to hang with the Walkabout crew and send Europa Clipper on its way to Jupiter. Join us for a preview of this mission's ambitious goals and the exciting journey it took to the launch pad. Also, new research suggests the Earth may escape a fiery death when the Sun becomes a red giant. We have, of course, space news, space histor...

Back in Black Holes 02.10.2024

We've got mini black holes as potential dark matter candidates and monstrous black holes spewing jets to cosmological scales. Who better than Top quark Jim Cooney to take us through these black holes? No one, that's who. We take a deep dive into meteorites, particularly those that have come from Mars. You may be surprised to learn how many we have, and now we know more about where those free Mars...

Black Hole Spindown Chirp and a 9-Day Geologic Rumble 18.09.2024

Gravitational waves may provide a new way to observe supernovae in our own Milky Way galaxy and determine when they produce black holes and when they result merely in neutron stars. Closer to home, scientists did some clever detective work to figure out the source of a mysterious 9-day seismic shaking here on Earth. The culprit: a giant, regular sloshing in a fjord triggered by a landslide as a re...

Recent Lunar Volcanic Activity and the Metallicity Cliff 11.09.2024

Tiny samples brought back from the Moon hint at surprisingly recent volcanic activity. What's up with that?! Elsewhere in the galaxy, a detailed study of over 100,000 stars identifies the metallicity cliff. This is where stellar composition that is low in heavy elements seems to inhibit the formation of at least some types of exoplanets. The astroquarks have all the details for you, as well as a P...

Adventures in Space the Cady Way 04.09.2024

The Astroquarks are joined by former NASA astronaut, PhD Chemist, and retired USAF Colonel Cady Coleman at Dragon Con 2024 for a wide ranging discussion of space flight, institutional challenges, training, flute playing, and more. 

Ocean World Mimas and the JUICE Slingshot 28.08.2024

Recent (astronomically speaking, of course!) perturbations to Mimas's orbit may be the explanation for the surprising presence of a global subsurface ocean in this tiny moon of Saturn. Meanwhile, the European Space Agency's JUICE (Jupiter Icy Moon Explorer) mission successfully completed a novel gravity assist making use of the Earth's Moon and the Earth to send it towards... Venus! We have all th...

Barney the Dinosaur Killer from Outer Space and Water Inside Mars 21.08.2024

New research shows that the asteroid that killed the dinosaurs some 66 million years ago formed in the colder, more distant reaches of the solar system. The Astroquarks have taken it upon themselves to dub this asteroid Barney. We'll update you on that new research and a surprising discovery from Mars Insight data that suggests Mars has a potentially huge amount of delicious H2O not to far beneath...

The Fermi Paradox - Are We Truly Alone? 14.08.2024

When Frank Drake created his famous eponymous equation to estimate the number of advanced communicative civilizations in the Milky Way, we had little more than educated guesses for most of the factors in that equation. Decades later we have much better data, and the answer seems to reinforce Fermi's famous paradox: why is our galaxy so silent? The role of plate tectonics in enabling evolution of a...

Chemical Whispers of Life on Mars 31.07.2024

The astroquarks assemble for their 365th episode, about 10 years after their first, with a look at a canceled mission to the Moon and tantalizing observations from an ongoing mission at Mars. The Perseverance rover has spied a particularly unusual rock sample with some tantalizing features. Join us for the deets as well as historical astronomy trivia, space news, and more.

Lunar Caves for Future Habitation 18.07.2024

In this light episode of Walkabout the Galaxy, Josh and Audrey discuss the first confirmation of open spaces in lava tubes connected to lunar pits on the Moon. 200 lunar pits have been observed on the Moon, and now scientists have used radar data to demonstrate that these pits are in fact connected to caverns that could provide future astronauts with a safe haven beneath the lunar surface. Join us...

Dark Matter, Deuterons, and a Mixed-Up Protoplanetary Disk 11.07.2024

You'll be amazed at how much we can learn from iron meteorites. Who would have guessed that analysis of the compositions of these humble metallic remnants of asteroids would be able to tell us about the shape of the protoplanetary disk? We'll learn about the latest clues to the early history of our solar system, the surprising abundance of deuterons in cosmic rays provides another indicator that w...

Cygnus X-3 and a Naked-Eye Nova 27.06.2024

The clock is ticking on T Coronae Borealis which seems primed to undergo a nova explosion this summer. That will make this otherwise faint star as bright as Polaris thanks to a burst of nuclear fusion reactions on the exposed surface of this white dwarf. Another curious binary system, Cygnus X-3, is beaming x-rays toward us thanks to some nifty photon processing in the disk surrounding this black...

Primordial Black Holes Make the Galaxy Go 'Round 20.06.2024

We take a look at some Beta Pic Disk shots before journeying back to the earliest era of the universe and the possible formation of primordial black holes. Some of these may have been only the size of an atom and would have long since evaporated through Hawking radiation. But they may have left an observable imprint for our powerful telescopes peering into the distant past, and their larger siblin...

Full Circle to the Origins of Carbon and Exotic Gravity 12.06.2024

The Astroquarks celebrate their 360 th episode with discoveries showing carbon much earlier in the universe than previously thought possible, and an exotic new proposal as an alternative to dark matter. Plus, we have radioactive trivia and a slew of space news with a busy week in rocket and spaceship activity.

Volcanic Activity on Venus RIGHT NOW! 05.06.2024

There is a mountain - or should we say a volcano - of evidence, building that suggests volcanic activity on Venus during the time of the Magellan mission in the 1990s. We'll dig into that, struggle to get our script right, ponder the Fantastic Voyage, upcoming spaceflight milestones, and much more.

Watery Erigone and Rogue Stars in the Milky Way 30.05.2024

New observations of Erigone, the parent body of an asteroid family, indicate its rocks are juicy with water. That makes it both a potential resource for future missions but also shows that asteroids may have played a big role in delivering water to the early Earth. Watery Erigone: it rhymes! You'll have to listen for details. And students discovered three high-speed wayward stars in the Milky Way,...

Dyson Spheres and a Molten Planet 15.05.2024

The Astroquarks delve into the possibility of giant alien constructs around stars, and the strange weather on a planet that is unreasonably close to its star. Join us for space news, trivia, and a fun exploration of odd topics in astronomy on Walkabout the Galaxy.

The Low Down on Big G and the Young Moon of Dinkinesh 08.05.2024

NASA's Lucy mission discovered a surprising moon of the small asteroid Dinkinesh on its way to the orbit of Jupiter. New studies of that moon, a contact binary, suggest it may have a surprisingly young age. Meanwhile, cosmologists continue to wrestle with various seemingly contradictory measurements. One model suggests a modification to that old Physics 1 standby, the gravitational constant (or is...

Dark Matter Wins Again 01.05.2024

A clever test of dark matter and an alternative theory of gravity to explain the motions of stars around galaxies results in another check in the win column for dark matter. Simulations with the modified model of gravity failed to explain the motions in the inner regions of galaxies. Meanwhile the search for a hypothesized large object in the distant reaches of our solar system has so far come up...

Surprises from Bennu and the Milky Way 03.04.2024

Analysis of the samples returned from the asteroid Bennu have revealed surprising assemblages of minerals that put new constraints on the origin of the solar system. And once Top Quark Jim Cooney stops giggling, he tells us about the discovery of an itsy-bitsy galaxy, if you can call it that, orbiting the Milky way. It has only dozens of stars, plus, probably some dark matter. Join us for these su...

The Dark Ages of the Universe 27.03.2024

We peer back in time both to the murky history of our own solar system and to the dark ages of the universe. The JWST has confirmed that dwarf galaxies were the first to illuminate the universe, putting an end to the dark ages that followed the cooling after the big bang. In our own corner of the universe, new research highlights how nearby stars can lead to dramatic changes in our planet's climat...

Listen to the Walkabout the Galaxy podcast in Replaio

Radio and podcasts in one app - free, with no sign-up. Install today and do not miss the launch

Get it on Google Play

Replaio is not a podcast publisher; show names, artwork and audio belong to their authors and are distributed through public RSS feeds.